<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-12-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001494904</issuerCik>
        <issuerName>Global Indemnity plc</issuerName>
        <issuerTradingSymbol>GBLI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001455952</rptOwnerCik>
            <rptOwnerName>Essex Equity Capital Management, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 HUDSON STREET</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10014</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001534789</rptOwnerCik>
            <rptOwnerName>Essex Equity Joint Investment Vehicle, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 HUDSON STREET</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10014</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001519005</rptOwnerCik>
            <rptOwnerName>Maher Basil</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ESSEX EQUITY CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>70 SOUTH ORANGE AVENUE, SUITE 105</rptOwnerStreet2>
            <rptOwnerCity>LIVINGSTON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001518965</rptOwnerCik>
            <rptOwnerName>Maher M. Brian</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ESSEX EQUITY CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>70 SOUTH ORANGE AVENUE, SUITE 105</rptOwnerStreet2>
            <rptOwnerCity>LIVINGSTON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2011-12-07</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1587</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>18.16</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1848890</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class A Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2011-12-08</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>4444</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>18.16</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1853334</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is a weighted average price.  These shares were purchased in multiple transactions at prices ranging from $18.14 to $18.18, inclusive.  The reporting person undertakes to provide Global Indemnity plc, any security holder of Global Indemnity plc, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within such range.</footnote>
        <footnote id="F2">The price reported is a weighted average price.  These shares were purchased in multiple transactions at prices ranging from $18.10 to $18.18, inclusive.  The reporting person undertakes to provide Global Indemnity plc, any security holder of Global Indemnity plc, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within such range.</footnote>
        <footnote id="F3">The amount of securities shown in this row is owned directly by Essex Equity Joint Investment Vehicle, LLC (the &quot;Fund&quot;).</footnote>
        <footnote id="F4">As the investment manager of the Fund, Essex Equity Capital Management, LLC (the &quot;Investment Manager&quot;) may be deemed to be a beneficial owner of the Issuer's securities held by the Fund.  The Investment Manager disclaims any beneficial ownership of any of the Issuer's securities reported herein for purposes of Section 16 of the Exchange Act, except to the extent of its pecuniary interest, if any.</footnote>
        <footnote id="F5">Each of Basil Maher and M. Brian Maher (collectively, the &quot;Individual Reporting Persons&quot;), as a member of the investment committee of the Investment Manager, may be deemed to be a beneficial owner of the Issuer's securities held by the Fund.  Each of the Individual Reporting Persons disclaims beneficial ownership of any of the Issuer's securities reported herein for purposes of Section 16 of the Exchange Act, except to the extent of his pecuniary interest, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John Liu, Chief Executive Officer of Essex Equity Capital Management, LLC</signatureName>
        <signatureDate>2011-12-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ John Liu, Chief Executive Officer of Essex Equity Capital Management, LLC, as Investment Manager for Essex Equity Joint Investment Vehicle, LLC</signatureName>
        <signatureDate>2011-12-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ John Liu, Attorney-in-Fact for Basil Maher</signatureName>
        <signatureDate>2011-12-09</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ John Liu, Attorney-in-Fact for M. Brian Maher</signatureName>
        <signatureDate>2011-12-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
